In projects where there is a gap between the real business requirements and the stated business requirements, agile methods are extremely helpful. Agile methods provide a solution to this problem by:

Completing the project quickly so that gap is significantly reduced.

Replacing the project manager with a Scrum master in order to expedite the project.

Purposefully building and reviewing prototypes and release versions to refine requirements.

Eliminating the documentation altogether from the project management approach.